Variable valve duration control devices have been the subject of much invention during the past few decades. U.S. Pat. No. 5,373,818 discloses but one example of such inventive activity. The '818 patent describes a variable duration valve operating system having at least one embodiment which is useful with bucket tappets. U.S. Pat. No. 6,932,035, which is assigned to the assignee of the present invention, and which is hereby incorporated by reference in its entirety in this specification, discloses a cylinder valve operating system which permits adjustment of valve lift, particularly with roller finger follower systems. The system of the '035 patent does not, however, provide for camshaft phasing.
The present system may be used with such systems as axially shiftable camshafts and other valve lift control devices to control both valve lift and valve or camshaft timing.